Afghanistan's Taliban militia is on the run, and the opposition Northern Alliance has captured most of the country's key cities, including the capital Kabul. What do the military advances mean for the main objective of the war on terror -- to flush out chief terrorism suspect Osama bin Laden and his Al-Qaeda network?

Prague, 15 November 2001 (RFE./RL) -- Shortly after the events of 11 September, U.S. Defense Secretary Donald Rumsfeld vowed to "drain the swamp" that provides refuge to the terrorists believed to be behind the attacks on New York and Washington.

The U.S. is now hoping that recent military advances in Afghanistan by the opposition Northern Alliance will help expose the men hiding in that swamp -- Osama bin Laden, the members of his Al-Qaeda terrorist network, and their top Taliban protectors.

Yesterday, Rumsfeld was optimistic about the task ahead: "Finding handfuls of people is, indeed, like finding needles in a haystack, and it is a complicated process. But because of all the pressure that has been put on across the globe -- the drying up of bank accounts, the numbers of arrests that have been made, the interrogations that have been held, the intelligence that has been gathered -- I think that every day we have a better chance of achieving our goals."

The Taliban's hasty retreat from Afghanistan's major cities leaves it in control of the southeast of the country, around the city of Kandahar, though Taliban fighters are still putting up resistance in a pocket of northern territory around Kunduz.

The Northern Alliance victories "tighten the noose" around bin Laden in several ways.

-- His area of safe haven has shrunk dramatically, along with his ability to move large distances without being detected.

-- Taliban defections to the Northern Alliance can yield intelligence.

-- Rumsfeld said U.S. special forces have set up checkpoints on roads connecting the north and south of the country to -- as he put it -- "stop people who ought to be stopped."

-- Pakistan reportedly moved troops and tanks to its southwest border with Afghanistan after hearing rumors that bin Laden may try to enter the country.

-- Also, U.S. war planes are said to have bombed a building where members of bin Laden's Al-Qaeda network are suspected to have gathered, killing a number of people inside. It is not known whether bin Laden was among the group.

John Pike is a defense analyst for Global Securities.org, based in Virginia. Pike puts it this way: "Certainly the hope is that it's going to be much more difficult for bin Laden to move around. It's much more likely that local civilians, if they saw him moving around, will report it and make it easier to catch him."

That's not to say bin Laden will surface any time soon. The wealthy Saudi-born militant spent years in Afghanistan helping the mujahedin fight off Soviet rule in the 1980s. Much of the cash he brought in was channeled into building projects that give him a distinct advantage today -- the ancient network of water trenches adapted as underground hideouts for troops and supplies.

Neil Partrick is a Middle East analyst at Britain's Royal United Services Institute for Defense Studies. He says this tunnel network could give bin Laden shelter for some months to come: "It is conceivable that he, like figures such as [Taliban leader] Mullah Omar and leaders in the Taliban, will move out of Kandahar, if they haven't already, to areas close by, perhaps heading towards the mountains, caves in which Afghan fighters of different stripes in the past in recent history have holed themselves up to avoid detection. In that context, the threatened guerrilla war by the Taliban could mean that bin Laden and figures within the Al-Qaeda network could hold out for some time."

But Partrick says the dizzying speed of events on the ground may make detection easier: "If the political complexion of the country continues to change as rapidly as it has done, and if -- there's speculation, for example -- Kandahar could fall, and if then the Northern Alliance are able to establish in partnership with various Pashtun leaders in the south and east of the country a genuinely authoritative government, then it may be that the forces of the government -- with considerably greater knowledge than outsider elements -- would be able to arrest people like bin Laden or eliminate them. I would imagine that would be the preferred strategy in many respects from the point of view of the U.S. and the U.K."

Analysts say it's one thing to have driven the Taliban out of the cities, and quite another to penetrate their rural strongholds.

Terrorism expert Peter Bergen interviewed bin Laden for CNN in 1997. He told Reuters TV that the territorial losses will be a psychological setback for the Taliban. But he added that bin Laden is now likely to use his well-honed guerrilla tactics to survive: "It's playing to his strengths to be fighting in the hills, and it's playing to the Taliban's strengths to be fighting in the hills. It's a lot easier to act as a guerrilla force than to hold major cities when you've a major army backed by the American air forces basically attacking you. It'll be more easy for them to hold those positions in the hills than it would be to hold the cities. But nonetheless, these victories must be a psychological blow to a lot of members of the Taliban."

For now, the Taliban leadership is still defiant. Spokesman Mullah Abdullah told the Pakistan-based Afghan Islamic Press agency that Omar is in a safe place in Kandahar and that bin Laden would rather die than be arrested by the U.S.

U.S. Defense Rumsfeld told "The New York Times" that bin Laden might even have access to a helicopter, which could take him to a waiting jet and help him escape from Afghanistan.